Further evidence of polygenic inheritance of partial resistance in barley to leaf rust,Puccinia hordei

Summary The latent period (LP) is a crucial component of partial resistance. Five cultivars, L94, Sultan (Su), Volla (Vl), Julia (Ju) and Vada (Va), representing the known range in partial resistance and LP were crossed in a diallel, and the F₁, F₂ and F₃ tested. The LP effectuated by the five cultivars is about 9, 10^1/2, 10^1/2, 13 and 15^1/2 days, respectively. The crosses Su×L94, Vl×L94 and Ju×L94 had an F₂ positively skewed. Their F₂ means were similar or only slightly larger than the F₁ means. The F₂ frequency distributions in the crosses Vl×Su, Ju×Su and Ju×Vl were normal or nearly so with F₁ and F₂ means similar to each other and to the mid-parent value. The crosses involving Va as a parent again showed a positive skewness but with F₂ means considerably larger than the F₁ moans.Most F₂'s ranged from the low parent to the high parent values without transgression. In the crosses Va×L94 (reported earlier) and Ju×L94 the parental values were not recovered among 216 and 154 F₂ plants, respectively. The cross Ju×Va showed transgression beyond the low parent, Ju.From these data it is concluded, assuming no linkage, that seven loci are involved. The + alleles (governing a longer LP) are thought to be distributed over the parents as follows: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGceaqabeaacaqGmb% GaaeyoaiaabsdacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabcca% caqGGaGaaeiiaiaab2cacaqGTaGaaeiiaiaabccacaqGGaGaaeiiai% aabccacaqGGaGaaeiiaiaabccacaqGTaGaaeylaiaabccacaqGGaGa% aeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeylaiaab2caca% qGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaa% b2cacaqGTaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaae% iiaiaabccacaqGTaGaaeylaiaabccacaqGGaGaaeiiaiaabccacaqG% GaGaaeiiaiaabccacaqGGaGaaeylaiaab2cacaqGGaGaaeiiaiaabc% cacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGTaGaaeyl% aiaabccaaeaacaqGtbGaaeyDaiaabccacaqGGaGaaeiiaiaabccaca% qGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGRaGaae4kaiaa% bccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGRaGaae% 4kaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcacaqG% RaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaab2% cacaqGTaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeii% aiaabccacaqGTaGaaeylaiaabccacaqGGaGaaeiiaiaabccacaqGGa% GaaeiiaiaabccacaqGGaGaaeylaiaab2cacaqGGaGaaeiiaiaabcca% caqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGTaGaaeylaa% qaaiaabAfacaqGSbGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqG% GaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcacaqGRaGaaeiiaiaabc% cacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcacaqGRaGaaeii% aiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeylaiaab2cacaqGGa% GaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUca% caqGRaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiai% aab2cacaqGTaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGa% aeiiaiaabccacaqGTaGaaeylaiaabccacaqGGaGaaeiiaiaabccaca% qGGaGaaeiiaiaabccacaqGGaGaaeiiaiaab2cacaqGTaaabaGaaeOs% aiaabwhacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGa% GaaeiiaiaabccacaqGGaGaae4kaiaabUcacaqGGaGaaeiiaiaabcca% caqGGaGaaeiiaiaabccacaqGGaGaae4kaiaabUcacaqGGaGaaeiiai% aabccacaqGGaGaaeiiaiaabccacaqGRaGaae4kaiaabccacaqGGaGa% aeiiaiaabccacaqGGaGaaeiiaiaabccacaqGRaGaae4kaiaabccaca% qGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGRaGaae4kaiaa% bccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaab2cacaqGTaGaae% iiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqG% GaGaaeylaiaab2caaeaacaqGwbGaaeyyaiaabccacaqGGaGaaeiiai% aabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcacaqGRaGa% aeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcaca% qGRaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaae4kaiaa% bUcacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaae% 4kaiaabUcacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqG% GaGaaeylaiaab2cacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabc% cacaqGGaGaae4kaiaabUcacaqGGaGaaeiiaiaabccacaqGGaGaaeii% aiaabccacaqGGaGaaeiiaiaabUcacaqGRaaaaaa!1BBA!\[\begin{gathered} {\text{L94 - - - - - - - - - - - - - - }} \hfill \\ {\text{Su + + + + + + - - - - - - - - }} \hfill \\ {\text{Vl + + + + - - + + - - - - - - }} \hfill \\ {\text{Ju + + + + + + + + + + - - - - }} \hfill \\ {\text{Va + + + + + + + + - - + + + + }} \hfill \\ \end{gathered} \]The genes are supposed to act additively (intermediate inheritance) with the exception of one locus (the 6th or 7th locus) which shows dominance for the shorter LP (for the-alleles). The effect of this locus on LP seems considerably larger than that of the other loci. There are indications of physiological barriers, which means that LP's shorter than the one of L94 or much longer than that of Va are not possible.The effect of + genes in genotypes governing LP's close to these barriers (with very few or very many + alleles respectively) is smaller than in genotypes governing intermediate LP's.     

小核盘菌保藏过程中活力和致病力影响因素研究

研究了小核盘菌保藏过程中活力和致病力影响因素,结果表明：接种后培养6 d的小核盘菌活力（以该菌在PDA平板上培养形成的菌落直径表示）和致病力（以该菌在蒲公英叶片上形成的菌斑直径表示）最大,分别为66.2 mm和52.9 mm。保藏期间小核盘菌的活力和致病力均随时间呈下降趋势。保藏90 d后,培养8 d的小核盘菌的活力和致病力最大,分别为31.7 mm和17.9 mm;培养4 d的小核盘菌的活力和致病力最小,分别为6.3 mm和2.6 mm。保藏期间低水活度有利于小核盘菌活力和致病力的保持,活力和致病力均随水活度的降低而增加。当水活度低于0.432时,活力和致病力不再增加,趋于稳定。低温有利于小核盘菌活力和致病力的保持, 25 ℃下保藏90 d的小核盘菌失去了全部活力和致病力,而-16 ℃下小核盘菌的活力和致病力仅分别下降25.8 %和 13.7%。     

湘中丘陵区"长防林"生态效益研究初报

通过对湘中丘陵区长江防护林生态效益的定位观测，分别对小流域小气候、坡面产流量、产沙量及输沙率的分析、对林地最大涵水能力及保土效果进行了探讨。     

Large cardamom (Amomum subulatum Roxb.) plantation — An age old agroforestry system in Eastern Himalayas

Large cardamom (Amomum subulatum Roxb.) is a shade loving plant grown in the Indian hill states of Sikkim and Dargeeling district of West Bengal. About 30 important tree species are used to provide shade to the cardamom plants. Alnus nepalensis, a deciduous, nitrogen fixing and fast growing tree, is the species most commonly underplanted with cardamom. In addition to providing shade, it is also used for fuelwood. The old trees are cut and young plants coming up are allowed to grow in cyclic order. The quick decomposing leaf litter of A. nepalensis also fertilises the cardamom plants. The nitrogen added to the soil in this way has been found to be as high as 249 kg/ha. Large cardamom thrives well in a moist soil, which is maintained by water diverted from seasonal springs on the upper slopes. The system is well suited to conserving soil, water and tree cover of the characteristically steep slopes of the region. Moreover, the management inputs required for growing cardamom are low but the crop gives a higher financial return than rice or maize. The shade trees used in the system are also a major source of fuel, fodder and timber, especially as access to state owned forests is restricted by legislation. However, increasing incidence of viral chirkey and foorkey disease, panicle rot and capsule borer are reducing the cardamom productivity. It has been observed that integrating dairying and apiculture will further augment profitability from large cardamom agroforestry system.     

松红蜡蚧成虫空间分布及抽样技术

分别选择被松红蜡蚧（CeroplastesrubensMaskell）为害的马尾松10株,为害程度为轻、中、重,从东、南、西、北、顶5个方位,每株5个轮次进行全面的虫口、枝条长度调查,结果表明：不同轮次之间差异极显著;不同方向的多重比较差异显著;不同方位的虫口密度板显著。该虫空间分布为聚集分布,回归方程为：M＝2．42＋0．69X,相关系数γ＝0．9745,平均拥挤度与均数相关性极显著;应用I(wao．s)提出的贯序抽样公式,在T（m）≥T（0）时,需要进行防治。     

湘西北山区“长防林”生态效益研究初报

湘西北山区长江防护林生态效益监测站，分别就“长防林”对小流域小气候、坡面产流量、产沙量、输沙率、林地最大涵水能力及保土效果进行了定位观测，资料分析表明，长防林生态效益十分显著。     

切梢小蠹伴生真菌发生及病害特征的初步研究

小长喙霉 ( Ophiostoma minus Hedgc.)于 190 6年作为新种定名为 Ceratostomella minorHedgc,1981年更名为 Ophiostoma minus Hedgc.,此后一直沿用至今 [1]。小长喙霉以小蠹虫( Tomicus spp.)为媒介 ,通过小蠹虫对树木的蛀害 ,被携带进入到寄主植物组织内 ,进行自身生命过程并危害寄主植物[2 ] ,故也被称为小蠹虫伴生真菌 [3,4] 。该菌的寄主植物主要是松树( Pinus spp.) [4] ,它在协助小蠹虫蛀害松树树木中扮演着重要的角色 [3,4]。80年代以来 ,纵坑切梢小蠹 ( Tomicus piniperda Linnaeus)在云南 8个地州大面积暴发成灾 ,10余万 hm2 …     

两种切梢小蠹生态学特性比较研究

纵坑切梢小蠹和横坑切梢小蠹是中国主要的森林蛀干害虫。在云南,两虫经常在云南松等松类树种上共同危害,造成重大生态和经济损失。这两种小蠹的种群结构因地区而异,其性比、成虫在枝梢上聚集危害的时间及其在树冠上的空间分布规律基本相同,但在树干上的空间分布规律有很大差异。通过研究并比较这两种小蠹的种群结构、性比、季节分布及空间分布等生态学特性差异,对防治有重要意义。     

曲线连续箱梁桥支座设置的比较

以实际工程为例,对采用MIDAS空间梁单元小半径曲线梁桥支座的布置进行计算和比较分析,并通过掌握小半径曲线梁桥支座受力特点,从而确定出适合该桥的支座布置形式。